William becomes Knight of the Garter in historic ceremony in Windsor

After indulging in one of his favourite pursuits - polo - over the weekend, there was an altogether more formal event on Prince William's agenda on Monday. In a historic ceremony the second-in-line to the throne was appointed the 1,000th ever Royal Knight of the Garter - the most senior British order of chivalry - by his grandmother the Queen.

The honour is traditionally given to those who have held public office, have contributed to national life or who have served the Queen personally. William has become one of the order's Royal Knight Companions, which recognises his seniority within the royal family.

Flanked by two 'supporter' knights - his father Prince Charles and his grandfather the Duke of Edinburgh - and clad in the traditional blue velvet cape and a black ostrich plume-adorned hat, Wills was officially appointed at a service at St George's Chapel in Windsor Castle.

Earlier the Queen had invested him with the order in the Castle's Garter Throne Room by putting a blue sash over his left shoulder as a page held an ancient blue velvet garter - which Edward III wore when establishing the order in 1348 - to his knee.